1. Field of the Invention
The invention relates to a driving support apparatus and a driving support method.
2. Description of Related Art
There has been disclosed a technique by which, when two white lines on a road have been detected as road markings that indicate lane boundaries, steering of a vehicle is controlled on the basis of these two white lines; whereas, when white lines cannot be detected, steering of the vehicle is controlled on the basis of distances to side walls (for example, see Japanese Patent Application Publication No. 10-031799 (JP-A-10-031799)). With the technique described in JP-A-10-031799, even when there is a thin spot or a break in white lines, it is possible to maintain control over steering of the vehicle on the basis of distances to side walls.
Incidentally, when the degree of curve of a running road on which a vehicle runs is large, a driver feels a collision risk on the basis of a distance or arrival allowance time to an object in the widthwise direction of the vehicle. On the other hand, when the degree of curve of a running road is small, the driver feels a collision risk on the basis of a distance or arrival allowance time to an object in the traveling direction of the vehicle. Therefore, in order to support driving without making the driver feel a collision risk as much as possible, it is necessary to change a determination criterion based on which running is supported in response to the degree of curve of a running road.